The present invention relates to a method and an apparatus for forming a laminated coil, for use in electrical equipment and communication equipment, including a wire and insulation films wound around a core.
Laminated coils wherein a wire for coil and insulation films are wound around a core are used in flyback transformers for use in cathode-ray tubes or the like.
An example of a conventional laminated coil is described below with reference to FIG. 4. An insulation film 3 of polyester is wound in a layer around a core 2. A wire 20 of copper is coiled around the insulation film 3 in a range by providing a predetermined gap at each of the lengthwise edges of the insulation film 3 therefrom to form an inner coil 21. Other insulation films 3 are wound in three layers around the inner coil 21. The wire 20 is coiled around the three layer's insulation films 3 in the above-described manner to form an outer coil 22. An insulation film 3 is wound in a layer around the outer coil 22. Then, the assembled body is sealed with resin.
FIGS. 5 and 6 show a conventional laminated coil forming apparatus, for example, disclosed in the examined Japanese Patent Publication No. 2-61129, which can carry out the above operations. A frame 44 is rotatably mounted on a machine base 41 via a bracket 43. Two spindles, first spindle 45a and second spindle 45b are projected from the frame 44 on both sides thereof in directions perpendicular to a rotary axis of the frame 44. Each of spindles 45a and 45b holds the core 2 as the core holding means 1. The frame 44 is intermittently rotated by 180 degrees by a driving device 46 in the same direction or a normal and reverse directions. Each of spindles 45a, 45b are rotated by a servo motor or pulse motor while holding the core 2. A wire winding mechanism 47 is located on the base 41 with the mechanism 47 opposed to the first spindle 45a of the core holding means 1 in FIGS. 5 and 6. A bracket 49 the mechanism 47 can move in horizontal and vertical directions on a base 48 of the base 41. The bracket 47 has at its leading end a nozzle 50 for supplying the wire. The wire is supplied to the nozzle 50 after a tensile force is applied by a tensile force adjusting mechanism (not shown) to the wire supplied from a bobbin 72 around which the wire is wound. Reference numeral 51 is an insulation film supply device. The device 51 includes a holding device 52 of a reel 74 around which the insulation film 3 is wound, rollers 53 for guiding the film 3 to a predetermined position, screw shafts 54 located in the vertical direction via a gap therebetween, a bracket 56 supported on the screw shafts 54 and movable in the vertical direction and pivotable in the back and front directions, chucks 57 mounted on the bracket 56 for holding the film 3, and a driving device 55 for reversely rotating the screw shafts 54.
Reference numeral 58 denotes an insulation film winding mechanism arranged at a position where the second spindle 45b is opposed to the mechanism 58. The mechanism 58 includes a winding device 60 for winding the film 3 around the core 2, an adhering device 61 for temporarily adhering the leading and trailing ends of the film 3 to the core 2, and a cutting tool 59 for cutting the film 3 in a predetermined length.
In such a device, firstly, the insulation film 3 is wound around the core 2 held by the second spindle 45b in FIGS. 5 and 6 by the film supply device 51 and then, the frame 44 is rotated by the driving device 46 by 180 degrees to oppose the core 2 held by the second spindle 45b to the wire winding mechanism 47. Then, the wire 20 is wound by the wire winding mechanism 47 around the core 2 held by the second spindle 45b. Then, after the wire winding is completed on the core 2 of the second spindle 45b, the frame 44 is again rotated by 180 degrees by the driving device 46 so that the core 2 held by the second spindle 45b is subjected to the insulation film winding operation. That is, the insulation films 3 are fed by the film supplying device 51 around the core 2 held by the second spindle 45b. During the film and wire winding operations, the core 2 held by the first spindle 45a is also subjected to the same operations. In such operations, the two laminated coils are simultaneously obtained in the device.
In the laminated coil, however, an insulation distance shown by a broken line 23 between the lengthwise edge of the inner coil 21 and that of the outer coil 22 is short. Thus, the laminated coil has an undesirable insulation characteristic.